The present invention relates to arrangements for generating waves in bodies of water in general, and more particularly to wave generating arrangements to be used in marine engineering test tanks or in public or private swimming pools.
There are already currently known two basic types of wave generating arrangements which may be distinguished from one another by the type of "beater" which is used therein and which dynamically operates on the body of water in which an artificial swell is to be provided.
First of all, there may be mentioned wave generating arrangements utilizing "paddle" type beaters which may be either mounted for vertical displacement and driven to produce an alternating vertical translatory motion, or mounted for an angular displacement and driven to produce an alternating rocking motion. Such paddles are either articulated to or connected with a device for translating the paddle rocking shaft
Studies carried out on these systems have shown that the transfer function thereof (i.e the ratio between the height of the swell produced and the height of the angular elongation of the paddle) are satisfactory only for double-acting systems and for short wave periods Furthermore, for technical reasons, such systems have only a low degree of attractiveness because of the mass to be moved, the difficulty of simultaneously controlling the movement of two rams (translation and rocking) and the technical complexities resulting from the need for providing and operating equipment that is required to ensure satisfactory sealing action between the paddles and the side walls of the channels in which the paddles are moving.
Secondly, there are to be mentioned "corner plunger" beaters which comprise a prism having a downwardly pointed triangular cross section, wherein one major surface of such a prism slides in an alternating motion over the length of the rear vertical wall of the channel The transfer function of this type of beater is not very satisfactory and, furthermore, such beaters cannot be adapted to very deep wave tanks in which the effects of both swell and current are to be simulated.
A new and more satisfactory solution was recently proposed This solution involves the use of a horizontally extending cylindrical float as a "beater". This float is sinusoidally actuated for movement in any one of three directions of motion.
Although this system produces a more satisfactory transfer function than those discussed above, it nevertheless has the disadvantage of being costly because of the complex method of operating the beater (ram and connecting-rod assembly).